Field of the Invention
Embodiments of the present invention include an apparatus and method for forecasting solar energy irradiance potential and subsequent photovoltaic output in a region.
Description of Related Art
Solar energy is becoming increasingly attractive to both retail and commercial consumers as a means to generate electricity. The main drawback to solar energy occurs when intermittent cloud cover moves over the solar field. This is known as solar resource intermittency. Currently, solar intermittency is only a small problem because the ratio of intermittent resources to fossil or nuclear energy sources is small. However, with increasing amounts of solar energy being integrated into electricity grids, solar intermittency can become a non-trivial problem for utilities.
Two methods of mitigating these intermittencies are currently employed by utilities. The first method involves generating electricity from another source and feeding that electricity to the area that was being supplied by solar. This electricity generation source can come from large scale batteries, fast responding natural gas generators or diverting electricity from one area to another. Batteries and other storage devices are being used to counteract the variation in power production from solar photovoltaic (PV) plants. These storage devices help maintain power quality as well as ensure that variability of distributed power generation does not cause unwanted uncertainty in power demand from the electric utility. A disadvantage of using batteries, however, is that they are expensive and susceptible to wear from excessive cycling. Calculations have shown that the integrated energy input/output to a battery system can be reduced by a factor of at least five if an approximately three minute forecast of PV production is available. A second mitigation strategy is to announce price signals and indicators specific to the occlusion event to incentivize a demand reduction, also known as a demand response. In both mitigation strategies, electricity quantities, either with excess electricity or shortage, have to be actively managed. Common to the success of electricity management with interment resources is a need for a forecast of solar energy irradiance potential and subsequent photovoltaic output predictions.